56-15-03 BELL: Applies to Model 47H1 Helicopters, Serial Numbers 1347 Through 1349 and 1351 Through 1371.
Compliance required as soon as possible but not later than August 15, 1956.
Failure of a control cable of the synchronized elevator control system can result in loss of control of the helicopter. Installation of the fail safe synchronized elevator centering spring, Bell Kit No. 47-2573-1, is mandatory and provides a self-centering device for the synchronized elevator so that control of the helicopter can be maintained in event of elevator control cable failure.
(Bell Mandatory Service Bulletin No. 109 dated June 15, 1956, covers this same subject.)